US-12620507-B2 - In-vehicle communication system and communication cable

US12620507B2US 12620507 B2US12620507 B2US 12620507B2US-12620507-B2

Abstract

An in-vehicle communication system includes a transmitter that transmits a differential signal, a receiver that receives the differential signal, and a communication cable that connects between the transmitter and the receiver and transmits the differential signal. The communication cable includes a twisted wire, a sheath covering the twisted wire, and a talc layer provided between the twisted wire and the sheath. The sheath includes a pair of ribs located across a straight line connecting a conductor center of a first coated wire and a conductor center of a second coated wire in a transverse section of the communication cable. The talc layer is provided along the surface of the twisted wire.

Inventors

Kenta Kobayashi
Kenichiro Iwama
Ayumu MINAGAWA

Assignees

SUMITOMO WIRING SYSTEMS, LTD.

Dates

Publication Date: 20260505
Application Date: 20221003
Priority Date: 20211021

Claims (11)

1 . An in-vehicle communication system comprising: a transmitter configured to transmit a differential signal; a receiver configured to receive the differential signal; and a communication cable connecting between the transmitter and the receiver and configured to transmit the differential signal, wherein the communication cable includes: a twisted wire in which a first coated wire and a second coated wire are twisted together; a sheath covering the twisted wire; and a talc layer provided between the twisted wire and the sheath, the sheath includes: a tubular part surrounding the first coated wire and the second coated wire; and a pair of ribs each extending spirally in an extension direction of the communication cable while protruding inward of the communication cable from the tubular part to between the first coated wire and the second coated wire, in a transverse section of the communication cable, the pair of ribs are located across a straight line connecting a conductor center of the first coated wire and a conductor center of the second coated wire, so as to demarcate a first space in which the first coated wire is disposed and a second space in which the second coated wire is disposed, the talc layer is provided along a surface of the twisted wire, a section of the communication cable in the extension direction is a straight section extending in a straight line, and another section thereof is a bent section extending in a bent manner, the pair of ribs demarcate the first space and the second space in both the straight section and the bent section, an inter-conductor distance between the first coated wire and the second coated wire is constant in both the straight section and the bent section, and an insulating coating of the first coated wire and an insulating coating of the second coated wire are not fused together.
2 . The in-vehicle communication system according to claim 1 , wherein the pair of ribs are provided to extend throughout an entire length of the sheath.
3 . The in-vehicle communication system according to claim 1 , wherein distal ends of the paired ribs are spaced apart from each other, and between the paired ribs, the first space and the second space communicate with each other, and the insulating coating of the first coated wire and the insulating coating of the second coated wire are in direct contact with each other not via the talc layer.
4 . The in-vehicle communication system according to claim 1 , wherein a pitch of spirals of each of the paired ribs is set to be constant throughout an entire length of the section in which the pair of ribs are provided.
5 . The in-vehicle communication system according to claim 1 , wherein one end portion and an opposite end portion of the communication cable in the extension direction are sheath outer sections in which the twisted wire extends outside the sheath, and a first connector for connecting the twisted wire to the transmitter is provided in the sheath outer section of the one end portion, and a second connector for connecting the twisted wire to the receiver is provided in the sheath outer section of the opposite end portion.
6 . The in-vehicle communication system according to claim 1 , wherein the sheath covers only the twisted wire and the talc layer.
7 . The in-vehicle communication system according to claim 1 , wherein powdered talc of the talc layer includes magnesium hydroxide and silicate, the powdered talc is white in color, and the sheath is a different color from the powdered talc.
8 . The in-vehicle communication system according to claim 1 , wherein the powdered talc of the talc layer has an average particle size from 1 μm to 20 μm.
9 . The in-vehicle communication system according to claim 1 , wherein a value of characteristic impedance of the communication cable in a bent state is from 94 Ω to 106 Ω inclusive measured with a characteristic impedance measurement method conforming to a measurement method defined in IEC 62153-1-1, except for a measurement sample being measured in a bent posture instead of a typical straight posture, where the bent posture is a posture in which an intermediate portion of the measurement sample is bent once around to form a loop having a bending radius of 20 mm, and the loop is hollow inside.
10 . The in-vehicle communication system according to claim 1 , wherein the value of the characteristic impedance of the communication cable is from 94 Ω to 106 Ω inclusive measured with the measurement method conforming to IEC 62153-1-1, after a fatigue test that is defined in ISO 19642-2 and uses a weight of 300 g and a mandrel having a diameter of 15 mm.
11 . A communication cable for use in an in-vehicle communication system configured to transmit and receive a differential signal, the communication cable comprising: a twisted wire in which a first coated wire and a second coated wire are twisted together; a sheath collectively covering the twisted wire; and a talc layer provided between the twisted wire and the sheath, wherein the sheath includes: a tubular part surrounding the first coated wire and the second coated wire; and a pair of ribs each extending spirally in an extension direction of the communication cable while protruding inward of the communication cable from the tubular part to between the first coated wire and the second coated wire, in a transverse section of the communication cable, the pair of ribs are located across a straight line connecting a conductor center of the first coated wire and a conductor center of the second coated wire, so as to demarcate a first space in which the first coated wire is disposed and a second space in which the second coated wire is disposed, the talc layer is provided along a surface of the twisted wire, a section of the communication cable in the extension direction is a straight section extending in a straight line, and another section thereof is a bent section extending in a bent manner, the pair of ribs demarcate the first space and the second space in both the straight section and the bent section, an inter-conductor distance between the first coated wire and the second coated wire is constant in both the straight section and the bent section, and an insulating coating of the first coated wire and an insulating coating of the second coated wire are not fused together.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a national phase of PCT application No. PCT/JP2022/036934, filed on 3 Oct. 2022, which claims priority from Japanese patent application Nos. 2021-172592 and 2022-086604, filed on Oct. 21, 2021 and May 27, 2022, respectively, all of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to an in-vehicle communication system and a communication cable. BACKGROUND Patent Document 1 discloses an interface circuit of a communication device that performs signal transmission between electrical devices in a vehicle. In the communication device of Patent Document 1, the signal transmission line of the interface circuit is constituted by a pair of differential transmission lines. PRIOR ART DOCUMENT Patent Document Patent Document 1: JP 2020-120242 A SUMMARY OF THE INVENTION Problems to be Solved In Patent Document 1, the pair of differential transmission lines in the interface circuit are connected to a cable via a connector. It is desirable to maintain a distance between conductors of the cable. In view of this, an object is to facilitate maintaining a distance between conductors of a cable installed in a vehicle. Means to Solve the Problem An in-vehicle communication system of the present disclosure includes a transmitter configured to transmit a differential signal, a receiver configured to receive the differential signal, and a communication cable connecting between the transmitter and the receiver and configured to transmit the differential signal, the communication cable including a twisted wire in which a first coated wire and a second coated wire are twisted together, a sheath covering the twisted wire, and a talc layer provided between the twisted wire and the sheath, the sheath including a tubular part surrounding the first coated wire and the second coated wire, and a pair of ribs each extending spirally in an extension direction of the communication cable while protruding inward of the communication cable from the tubular part to between the first coated wire and the second coated wire, the pair of ribs, in a transverse section of the communication cable, being located across a straight line connecting a conductor center of the first coated wire and a conductor center of the second coated wire, so as to demarcate a first space in which the first coated wire is disposed and a second space in which the second coated wire is disposed, and the talc layer being provided along a surface of the twisted wire. Effect of the Invention According to the present disclosure, maintaining a distance between conductors of a cable installed in a vehicle is facilitated. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an in-vehicle communication system according to a first embodiment. FIG. 2 is a schematic block diagram showing the in-vehicle communication system according to the first embodiment. FIG. 3 is a plan view showing a communication cable. FIG. 4 is a cross-sectional view along line IV-IV in FIG. 3. FIG. 5 is a diagram illustrating an example of a bent section of a communication cable. FIG. 6 is a diagram showing an end portion of the communication cable. FIG. 7 is a diagram showing evaluation results of communication cables. FIG. 8 is a diagram showing evaluation results of communication cables. FIG. 9 is a cross-sectional view showing a communication cable of sample S8. FIG. 10 is a cross-sectional view showing a communication cable of sample S13. FIG. 11 is a diagram showing a bent posture of the communication cable when measuring characteristic impedance in a bent state. DETAILED DESCRIPTION TO EXECUTE THE INVENTION Description of Embodiments of Disclosure Initially, modes of the present disclosure will be enumerated and described. An in-vehicle communication system of the present disclosure is as follows. (1) An in-vehicle communication system including a transmitter configured to transmit a differential signal, a receiver configured to receive the differential signal, and a communication cable connecting between the transmitter and the receiver and configured to transmit the differential signal, the communication cable including a twisted wire in which a first coated wire and a second coated wire are twisted together, a sheath covering the twisted wire, and a talc layer provided between the twisted wire and the sheath, the sheath including a tubular part surrounding the first coated wire and the second coated wire, and a pair of ribs each extending spirally in an extension direction of the communication cable while protruding inward of the communication cable from the tubular part to between the first coated wire and the second coated wire, the pair of ribs, in a transverse section of the communication cable, being located across a straight line connecting a conductor center of the first coated wire and a conductor center of the second coated wire, so as to demarcate a first space in which th